Hello
Here is a french RTS game called "Stratageme"
findable on my website where I gather my creations in various areas: programs, games, drawing, writing, and now music.
some screenshots :
Here, enter the name of the game

If you can not click on the cross

and finally, enter the number of players. If you are alone, type 1. The party will not launch until all the players are connected.
You can test the program by running it several times and create a LAN party with your single computer.

I let you discover the game and its multiple features.

Regarding the map editor.
Here are the keys:
T: Select the map size
S: Save, choose the name
Left click: to put texture / Objects
Right click + X or W: Changes the height of the terrain
A and Z: Select the texture or object
O: mode field / Objects
1-8: selected camp